Address Ameba errors

src/spectator/abstract_expression.cr

@@ -47,7 +47,7 @@ module Spectator
     # This consists of the label (if one is available) and the value.
     def inspect(io)
       if (label = @label)
-        io << @label
+        io << label
         io << ':'
         io << ' '
       end

src/spectator/lazy.cr

@@ -8,8 +8,8 @@ module Spectator
     # The block should return the value to store.
     # Subsequent calls will return the same value and not yield.
     def get(&block : -> T)
-      if (value = @value)
-        value.get
+      if (existing = @value)
+        existing.get
       else
         yield.tap do |value|
           @value = Value.new(value)